Electronics cabinet with fire extinguishing apparatus



C. W. TERRY Oct. 1, 1968 ELECTRONiCS CABINET WITH FIRE EXTINGUISHING APPARATUS Filed April 27, 1966 INVENTOR. CYRL W. TERRY BY;

ATTORNEY.

United States Patent Office 3,403,733 Patented Oct. 1, 1968 3,403,733 ELECTRONICS CABINET WITH FIRE EXTINGUISHING APPARATUS Cyril W. Terry, Oxnard, Califi, assignor to the United States of America as represented by the Secretary of the Navy Filed Apr. 27, 1966, Ser. No. 546,480 9 Claims. (Cl. 1692) ABSTRACT OF THE DISCLOSURE The description discloses a fire extinguishing system for an electronics cabinet. The system includes a duct means which extends between upper and lower openings which open into an inner portion of the cabinet. Mounted within the duct means there may be a venturi and extending through the duct means there may be a tube for discharging a fire extinguishing fluid into the throat of the venturi. Accordingly, when a fire occurs within the electronics cabinet the discharge of this fire extinguishing fluid into the venturi draws hot gases from the top of the cabinet, mixes them with the fluid where the gases are cooled, and then the resulting mixture is forced into the bottom portion of the cabinet. This circulation will extinguish a fire within the cabinet.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to an electronics cabinet and a fire extinguishing apparatus wherein a fire extinguisher is mounted to an electronics cabinet and is capable of quickly extinguishing a fire therein without damage to electronics components within the cabinet.

The most commonly used method of extinguishing a fire within an electronics cabinet is to open one of the cabinet doors and discharge carbon dioxide into the interior spaces. This method has several serious disadvantages. When carbon dioxide is discharged from a fire extinguisher expansion and absorption of heat take place which results in the conversion of some of the carbon dioxide to a solid form, sometimes called snow. Carbon dioxide in this snow form is ineffective as a fire extinguisher agent until it sublimes or is converted to a gas. Further, when this snow is directed against heated parts of sensitive electronics components a high degree of thermal shock results which often causes permanent injury to these parts. The present method also suffers from the disadvantage that the cabinet must be open to introduce the fire extinguishing agent. This opening allows air to enterinto the cabinet to support the combustion therein. There has been a need for a device which will effectively extinguish a fire within an electronics cabinet without any resulting damage to electronics parts therein.

The present invention provides a fire extinguisher which can be mounted to an electronics cabinet or similar housing for developing an inert atmosphere which will completely fill the cabinet and remove any support for combustion therein. Pressurized carbon dioxide or a similar fire extinguishing media may be utilized with the invention without the danger of snow developing to injure the sensitive electronics parts. In operating the invention no openings are made to the atmosphere and a closed cycle principle is utilized to remove the hot gases which are supporting combustion within the cabinet and mix these gases with the fire extinguishing media to form an inert mixture which is introduced into the cabinet. This may be accomplished by a duct which is mounted to the exterior of the cabinet and extends between upper and lower inner portions thereof; a jet blower which is mounted within the duct means with its discharge end directed in a downward direction; and a bottle of fire extinguishing fluid which is connected to the jet blower so that when the fire extinguishing fluid is released hot air -is drawn from the top of the cabinet and mixed with the fire extinguishing fluid in the jet blower to form an inert gaseous mixture. This inert mixture is introduced into the lower portion of the cabinet for extinguishing the fire.

An object of the present invention is to provide a housing and fire extinguisher which is more effective than prior art devices for extinguishing a fire within the hous- Another object is to provide a housing and fire extinguisher wherein the fire extinguisher operates on a closed cycle principle, thereby eliminating the need of opening the housing to the outside atmosphere;

A further object of the present invention is to provide a method of quickly and effectively extinguishing a fire within a housing without any damage to components therein;

Yet another object is to provide an electronics cabinet and fire extinguisher which is capable of effectively a fire within the electronics cabinet without damage to the electronic components therein.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invent-ion when considered in conjunction with the accompanying drawing wherein:

FIG. 1 is an isometric view of a computer cabinet and the fire extinguisher device with portions cut away to illustrate various details and with the exterior of the cabinet shown in phantom;

FIG. 2 is a view taken along plane II-II of FIG. 1; and

FIG. 3 is a view taken along plane III-III of FIG. 2.

Referring now to the drawing wherein like reference numerals designate like or similar parts throughout the several views there is shown in FIG. 1 a housing such as a computer cabinet 10 which contains many sensitive electronics components (not shown). The cabinet 10 has an upper inner portion 12 and a lower portion 14 which may be defined generally as the upper half volume and lower half volume of the cabinet respectively. When a fire occurs within the cabinet the hot gases rise into the upper portions of the cabinet and the cooler gases remain therebelow. The invention is adapted to very effectively utilize this phenomenon to quickly extinguish any fire that may develop within the cabinet 10.

The electronics cabinet 10 has an upper opening 16 which opens into the upper inner portion 12, and a lower opening 18 which opens into the lower inner portion 14 of the electronics cabinet. A duct 20 is mounted to the exterior of the cabinet 10 and may extend substantially vertically between the upper and lower openings 16 and 18 for communicating the upper and lower inner portions 12 and 14 of the cabinet with one another. As shown in FIG. 1, the duct may be generally U-shaped with its top opening connected to the cabinet at the upper opening 16 and its bottom opening connected to the cabinet at the lower opening 18. The top and bottom openings of the duct 20 may be provided with flanges so that bolts or sheet metal screws 22 may be used for mounting the duct rigidly to the cabinet 10. This mounting exposes the top end of the duct to the upper inner cabinet portion 12 where the hot gases generally reside, and the bottom opening of the duct to the lower inner cabinet portion 14 where the cooler gases generally reside.

Mounted within the duct 20 is a jet blower 24 with its discharge end 26 directed downstream from the top opening of the duct. The jet blower 24 may be mounted within an enlarged portion of the upright portion of the duct with the discharge end 26 directed in a substantially downward direction. Many types of jet blowers may be employed with this invention and as an example I have shown a jet blower which has two consecutive intake body venturi portions 28. As shown in FIGS. 2 and 3 the tube 40 may be directed downwardly with the terminal end connected to a nozzle 27. The nozzle 27 may be connected to the top body venturi portion by a spider 30 which has radial arms which are welded to the discharge end of the nozzle 27 and the intake end of the top body venturi portion. The top body venturi portion 28 may be similarly connected to the bottom body venturi portion. The jet blower assembly 24 may be connected to the interior of the duct 20 by a pair of spiders 32 which have radial arms connected at outer ends to the inner surface of the duct and inner ends connected to the nozzle 27 and bottom body venturi portion 28 by any suitable means such as welding. To further enhance the venturi effect the generally upright portion of the duct may be provided with a throat or constriction 34. The portion of the duct below the constriction 34 may be enlarged, as shown in FIG. 1, for the purpose of slowing down the stream of gases within the duct prior to entering the cabinet 10. The portion of the duct above the constriction 34 may also be enlarged and forms along with the body venturi portions 28 the last of a series of intake body venturi portions prior to the constriction 34.

Connected to the intake end of the jet blower 24 is a pressurized container 36 which contains a fire extinguishing media. The container 36 may have a selectively operable valve 38 and may be connected to the intake of the jet blower 24 by a tube or pipe 40 which extends through the wall of the duct 20 and is connected to the intake of the nozzle 27 by any suitable means such as a friction fit or welding. Various couplings may be interposed within the pipe 40 for the purpose of disconnecting the pipe components as well as the pressurized container 36. When the valve 38 is opened the pressurized fire extinguishing media is discharged into the jet 'blower 24 and the constriction 34 thereby causing hot gases to be withdrawn from the cabinet, mixed violently within the jet blower to provide an inert gaseous mixture 42 which is discharged within the lower inner portion 14 of the cabinet.

There may be mounted in the lower inner portion 14 of the cabinet an expansion chamber 44 for the purpose of reducing the velocity of the inert gaseous stream which is discharged from the duct 20 and disseminating this inert gaseous mixture within the lower inner portion 14 of the cabinet. The expansion chamber 44 may be mounted on the back inner side of the cabinet, as shown in FIG. 1 and has an opening which is connected to the bottom opening of the duct 20. The opening of the expansion chamber may be provided with an outwardly extending peripheral flange so that it can be connected to the bottom opening of the duct 20 by the screws 22. The expansion chamber 44 may be further provided with an inwardly extending peripheral fiange 46 so that screws 48 may be utilized to rigidly mount the expansion chamber to the back inner wall of the cabinet. Inside of the cabinet the expansion chamber 44 has a stries of openings 50 which are arranged to evenly distribute the inert gaseous mixture within the lower inner portion 15 of the cabinet.

Many types of fire extinguishing substances may be utilized, however extinguishing substances which are heavier than air are preferred for the operation of this invention. I have found that carbon dioxide works very successfully since it is heavier than air and will develop an inert gaseous mixture which will reside in the bottom inner portion 14 of the cabinet. Further, the rapid expansion of the carbon dioxide from a liquid state to a gaseous state, upon discharge from the nozzle 27, develops a high velocity flow which enhances the venturi effect for drawing hot gases from the upper inner portion 12 of the cabinet and provides an extremely low temperature to effectively lower the temperature of these hot gases. Also I have found that Freon #1301 manufactured by Du Pont works very satisfactorily.

Operation When an electronics fire occurs within the cabinet 10 all ventilation openings are closed and the valve 38 is opened to introduce the fire extinguishing substance in the jet blower 24. Hot gases, which are supporting combustion, will have already risen within the cabinet 10 and will be withdrawn through the upper opening 16 by the venturi effect of the jet blower 24 and constriction 34. These hot gases containing some oxygen will be violently mixed within the jet blower 24 as well as therebelow to develop the inert gaseous mixture 42 which is very low in temperature and will not support combustion. This mixing effect eliminates any possibility that snow will develop in the resulting mixture, thereby overcoming the problem of snow depositing on the sensitive electronic components within the cabinet 10. The downward stream of the inert gaseous mixture 42 is discharged from the duct 20 into the expansion chamber 44 Where it is evently distributed within the lower inner portion 14 of the cabinet through the chamber openings 50. The inert gaseous mixture 42 will quickly cool the electronics components and upon being heated will rise within the cabinet to recycle through the duct 20.

The method of the present invention is to withdraw gases from an upper portion of the cabinet, mix these gases with a fire extinguishing substance to form an inert atmosphere and introduce the inert atmosphere into the lower inner portion 14 of the cabinet.

In the broader concepts of the invention the venturi effect could be created within the duct 20 by simply introducing the fire extinguishing substance downstream within the vertical portion, such as through the tube 40 only. The stream of the pressurized fire extinguishing substance will draw the hot gases from the cabinet, however they will not be as thoroughly mixed as they are with the use of the jet blower 24. Conceivably the jet stream could even be reversed in direction and still support the broader concepts of the invention, however cooler gases from the lower inner portion 14 of the cabinet would then be withdrawn from the cabinet rather than the hotter gases which exist in the upper inner portion 12. t

It is now readily apparent that the present invention provides a very simple fire extinguishing device which may be mounted to an electronics cabinet for the purpose of quickly extinguishing any fire therein without any damage to the electronic components.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced other-wise than as specifically described.

I claim:

1. A housing with a fire extinguishing apparatus comprising:

said housing having a pair of openings which open into the housing inner area;

duct means mounted to said housing and extending between said openings for communicating inner portions of the cabinet with one another;

said duct means having a venturi which has intake and outlet ends and a throat therebetween;

tube means having a pair of tube ends;

one of said tube ends being adapted for connection to a pressurized fire extinguishing source means; and said tube means extending through the duct means and mounted with the other tube end directed toward the throat of the venturi, where-by upon connecting said one tube end to the pressurized fire extinguishing source means and discharging fire extinguishing media through said other tube end gases will be withdrawn from the housing through one of its openings by the venturi effect, mixed with the fire extinguishing media, and forced into the housing through the other housing opening.

2. A housing with a fire extinguishing apparatus as claimed in claim 1 wherein:

one of the openings opens into an upper inner portion of the housing and the other opening opens into a lower inner portion of the housing; and

said other tu be end also being directed substantially along the path of the duct means toward the housings lower opening.

3. A housing with a fire extinguishing apparatus as claimed in claim 2 including:

said pressurized fire extinguishing source means;

said one tube end being connected to the pressurized fire extinguishing source means; and

said pressurized fire extinguishing source means containing liquid carbon dioxide.

4. An electronics cabinet with a fire extinguishing apparatus comprising:

said cabinet having an upper opening which opens into an upper inner portion of the cabinet and a lower opening which opens into a lower inner portion of said cabinet;

duct means mounted to said cabinet and extending between said upper and lower openings for communicating the upper and lower inner portions of the cabinet with one another;

a nozzle mounted within said duct means with its discharge end directed substantially along the path of the duct means toward the cabinets lower opening; and

tube means connected to the intake end of the nozzle and extending through the duct means for connection to a pressurized fire extinguishing fluid source means,

whereby upon the occurrence of a fire within said cabinet a release of the fire extinguishing fluid into the nozzle will draw hot air through the upper opening, mix it with the fluid and discharge the mixture through the lower opening into the lower inner portion of said cabinet.

5. An electronics cabinet with a fire extinguishing apparatus as claimed in claim 4 including:

a pressurized container which contains a fire extinguishing fluid and has a valve means for selectively discharging said fluid; and

said tube means being connected to said valve means.

6. An electronics cabinet with a fire extinguishing apparatus as claimed in claim 5 wherein:

the fire extinguishing fluid is carbon dioxide.

7. An electronics cabinet 'with a fire extinguishing apparatus as claimed in claim 6 wherein:

said duct means having a venturi which has intake and outlet ends and a throat therebetween; and

said nozzle being directed toward the throat of said venturi.

8. An electronics cabinet with a fire extinguishing apparatus as claimed in claim 7 including:

an expansion chamber mounted in the lower inner portion of the cabinet and opening into said duct means through the lower opening; and

said chamber having discharge ports for disseminating said mixture within the lower inner portion of said cabinet.

9. An electronics cabinet with a fire extinguishing apparatus as claimed in claim 8 including:

a jet blower mounted in said duct means above said venturi.

References Cited UNITED STATES PATENTS 633,807 9/1899 Clayton 16912 661,497 11/1900 Clayton 169-12 702,713 '6/1902 Febiger 16911 702,714 6/1902 Febiger 169-11 1,254,582 1/1918 Decker 16912 1,507,053 9/ 1924 Flory et al. 1692 2,091,197 8/1937 Edmundson 169-12 2,630,183 3/1953 Foutz 16915 3,019,843 2/ 1962 Powell 1692 M. HENSON WOOD, JR., Primary Examiner.

H. NATTER, Assistant Examiner. 

